1. Technical Field of the Invention
The present invention generally relates to a differential gear assembly wherein pinion gears are supported within a differential housing such that the differential housing can be made lighter. More specifically, the present invention relates to a differential gear assembly wherein the pinion gears are supported directly by a ring gear.
2. Description of the Prior Art
In an automotive vehicle, a differential gear assembly is used to transfer power from a rotating driveshaft to the axles and wheels of the vehicle. The rotating driveshaft of the vehicle engages a ring gear which is mounted onto a differential housing. The end of the driveshaft and the ring gear are adapted to transfer rotation from the drive shaft to the differential housing such that the differential housing rotates transverse to the driveshaft. Within the differential housing, the ends of the axles of the vehicle are supported and connected to the differential housing through a differential gear set, such as a bevel differential gear set. Thus, the ring gear of the differential housing allows the driveshaft to rotate the differential housing in a direction transverse to the driveshaft, whereby the differential gear set rotates the axles of the vehicle to drive the wheels of the vehicle.
Typically the differential gear set includes a pair of side gears which are attached directly to the axles, and a pair of pinion gears which intermesh with the side gears. Most commonly, the pinion gears are supported by a pinion pin which extends across the differential housing. The pinion gears are allowed to rotate on the pinion pin thereby allowing the vehicle axles to rotate relative to one another.
The rotational load is thus transferred from the driveshaft, to the ring gear, through the differential housing and to the pinion pin. Therefore, the differential housing must be large and thick so as to support the load being transferred therethrough. Additionally, the weakest link in a conventional differential gear assembly is the pinion gear because the pinion gear has a hole extending therethrough to receive the pinion pin.
As seen from the above, there is a need to improve the structural integrity of a differential gear assembly while also decreasing weight.
It is therefore an object of this invention to provide a differential gear assembly with a differential housing and a ring gear having features which allow the pinion gears to be supported directly by the ring gear, thereby eliminating the pinion pin and the need for a hole through the pinion gears, removing the differential housing from the load path, and allowing the differential housing to be designed with less structural size and weight.
The disadvantages of the prior art are overcome by providing a differential gear assembly, in accordance with the present invention, in which the pinion gear is attached directly to the ring gear, thereby removing the differential housing from the load path, and eliminating the pinion pin and the hole through the pinion gear.
In the present invention, the differential gear assembly includes a plurality of pinion gears having an outwardly facing first side and an inwardly facing second side and a ring gear which engages the first side of the pinion gears such that the pinion gears are rotationally supported directly by the ring gear.
Also in the present invention the ring gear includes a plurality of recesses spaced radially thereabout and each of the pinion gears includes a projection extending from the first side, whereby each of the recesses receives one of the projections. The differential gear assembly further includes a first support ring having a plurality of holes formed thererein and each of the pinion gears includes a recess formed within the second side thereof. Each one of the holes is aligned with a recess of one of the pinion gears and a dowel or pin is inserted within each of the holes so as to extend into the recess.
In yet another aspect of the present invention, the differential gear assembly includes a second support ring adapted to fit within the first support ring thereby secure the pins within the holes.